1. Field of the Invention
Aspects of the present invention relate generally to identifying signal loss caused by defective areas in recording media, and more particularly to a media defect compensation system and method that decouple effects of asymmetry from baseline error compensation computations.
2. Description of Related Art
Recording media (e.g., those employed in conjunction with electronic devices) typically have one or more defects. “Defects” in this context may be caused by inefficiencies or inaccuracies associated with manufacturing processes, impact damage (e.g., scratches) or surface smudges caused by mishandling, particulate contamination, and asymmetry, among other factors. Irrespective of the source, such defects tend to cause variations in signals reproduced from the recording medium; for example, defects can result in weak signals, a baseline error or shift in the reproduced signal, or a total loss of signal when a reading device tries to read data from a defective location on a recording medium. Various conventional compensation strategies attempt to eliminate the errors such defects tend to cause in reading data from various media.
In optical storage media, asymmetry is a common distortion. When asymmetry occurs, pit length on a disc becomes longer than the nominal pit length and land length becomes shorter, or vise-versa. Asymmetry can cause the readback signal to become offset; direct current (DC) errors can be greater in some places in the data stream than in others. While attempts have been made to model asymmetry, traditional baseline error compensation techniques do not take into account its effects, and so are adversely affected by asymmetry.
Therefore, it may be desirable in some instances to provide a media defect compensation system and method that decouple effects of asymmetry from baseline error compensation computations.